On 2/20/2014 10:23 AM, Jiang Liu wrote:
Fix regression caused by commit b072e53, which breaks loading nouveau driver on optimus laptops.
On some platforms, ACPI _DSM method (nouveau_op_dsm_muid, function 0) has special requirements on the fourth parameter, which is different from ACPI specifications. So revert to the private implementation to check availability of _DSM functions instead of using common acpi_check_dsm() interface.
Reported-and-Tested-by: Maarten Lankhorst maarten.lankhorst@canonical.com Signed-off-by: Jiang Liu jiang.liu@linux.intel.com
I'm taking this, because the commit that introduced the regression went in through my tree.
In the future I'll appreciate CCing ACPI-related patches to linux-acpi, however.
Thanks, Rafael
drivers/gpu/drm/nouveau/nouveau_acpi.c | 26 ++++++++++++++++++++++++-- 1 file changed, 24 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/nouveau/nouveau_acpi.c b/drivers/gpu/drm/nouveau/nouveau_acpi.c index 4ef83df..83face3 100644 --- a/drivers/gpu/drm/nouveau/nouveau_acpi.c +++ b/drivers/gpu/drm/nouveau/nouveau_acpi.c @@ -106,6 +106,29 @@ static int nouveau_optimus_dsm(acpi_handle handle, int func, int arg, uint32_t * return 0; }
+/*
- On some platforms, _DSM(nouveau_op_dsm_muid, func0) has special
- requirements on the fourth parameter, so a private implementation
- instead of using acpi_check_dsm().
- */
+static int nouveau_check_optimus_dsm(acpi_handle handle) +{
- int result;
- /*
* Function 0 returns a Buffer containing available functions.* The args parameter is ignored for function 0, so just put 0 in it*/- if (nouveau_optimus_dsm(handle, 0, 0, &result))
return 0;- /*
* ACPI Spec v4 9.14.1: if bit 0 is zero, no function is supported.* If the n-th bit is enabled, function n is supported*/- return result & 1 && result & (1 << NOUVEAU_DSM_OPTIMUS_CAPS);
+}
- static int nouveau_dsm(acpi_handle handle, int func, int arg) { int ret = 0;
@@ -207,8 +230,7 @@ static int nouveau_dsm_pci_probe(struct pci_dev *pdev) 1 << NOUVEAU_DSM_POWER)) retval |= NOUVEAU_DSM_HAS_MUX;
- if (acpi_check_dsm(dhandle, nouveau_op_dsm_muid, 0x00000100,
1 << NOUVEAU_DSM_OPTIMUS_CAPS))
if (nouveau_check_optimus_dsm(dhandle)) retval |= NOUVEAU_DSM_HAS_OPT;
if (retval & NOUVEAU_DSM_HAS_OPT) {